Exploiting residual cocoa biomass to extract advanced materials as building blocks for manufacturing nanoparticles aimed at alleviating formation-induced oxidative stress on human dermal fibroblasts.

Abstract

The global adoption of by-product valorisation processes aligns with the circular economy framework, ensuring sustainability in the agricultural sector. In cocoa production, residual biomass can offer the opportunity to extract advanced materials, contributing to nanotherapeutic solutions for biomedical applications. This study explores extraction processes for valorising cocoa pod husks (CPHs) and optimising valuable cocoa-derived biocompounds for enhanced health benefits. Various extraction processes are compared, revealing the significant influence of CPH powder amount and extraction time. Furthermore, metabolic analysis identifies 124 compounds in the metabolite mix, including tartaric acid, gluconic acid and bioactive agents with antioxidant properties, resulting in a high total phenolic content of 3.88 ± 0.06 mg g-1. Moreover, the extracted pectin, obtained through alkaline and enzymatic routes, shows comparable yields but exhibits superior antioxidant capacity compared to commercial pectin. The study progresses to using these extracted biocompounds to develop Layer-by-Layer multifunctionalised nanoparticles (LbL-MNPs). Physico-chemical characterisation via ζ-potential, FTIR-ATR, and XPS confirms the successful multilayer coating on mesoporous silica nanoparticles (MNPs). TEM analysis demonstrates a uniform and spherical nanoparticle morphology, with a size increase after coating. In vitro biological characterisation with neo-dermal human fibroblast cells reveals enhanced metabolic activity and biocompatibility of LbL-MNPs compared to bare MNPs. Also, the engineered nanoparticles demonstrate a protective effect against H2O2-induced intracellular oxidative stress on human dermal fibroblast cell lines, showcasing their potential as antioxidant carriers for biomedical applications.